Spring adjustment mechanism

ABSTRACT

An adjustable spring loading mechanism for use in controlling the movement of doors and the like. The mechanism includes a cylinder housing and a piston slideable within the housing. An adjustable biasing mechanism selectively increases the load on the springs in the cylinder. The mechanism comprises a plurality of biasing means in the housing in engagement with the piston and arranged to apply individual biasing forces to the piston which cooperate to produce a total resultant force. Load adjustment means are engaged with each biasing means to vary the individual biasing forces to thereby proportionately vary the resultant force.

United States Patent [191 Lasier 1 Oct. 14, 1975 SPRING ADJUSTMENT MECHANISM [75] Inventor: Thomas R. Lasier, Princeton, Ill.

[73] Assignee: LCN Closers, Princeton, ll].

[22] Filed: Feb. 15, 1974 [21] Appl. No.: 442,742

Related US. Application Data [63] Continuation of Ser. No. 189,316, Oct. 14, 1971,

Primary ExaminerPaul R. Gilliam Assistant Examiner-D. L. Troutman Attorney, Agent, or FirmCharles E. Quarton [57] ABSTRACT An adjustable spring loading mechanism for use in controlling the movement of doors and the like. The mechanism includes a cylinder housing and a piston slideable within the housing. An adjustable biasing mechanism selectively increases the load on the springs in the cylinder. The mechanism comprises a plurality of biasing means in the housing in engagement with the piston and arranged to apply individual biasing forces to the piston which cooperate to produce a total resultant force. Load adjustment means are engaged with each biasing means to vary the individual biasing forces to thereby proportionately vary the resultant force.

4 Claims, 5 Drawing Figures US. Patent Oct. 14,1975 3,911,527

.fizaezfor 7%aw12faa3cn SPRING ADJUSTMENT MECHANISM This application is a continuation of co-pending application Ser. No. 189,316, filed on Oct. 14, 1971 by Thomas R. Lasier for SPRING ADJUSTMENT MECHANISM and now abandoned.

This invention relates generally to an adjustable and variable spring loading mechanism.

There is a constant need for improved spring adjustment mechanisms which are variable within a broad spectrum. The need for such mechanisms is particularly prevalent in the door closer field. As well-known by those skilled in the art, the operating requirements for door closers depend upon the physical characteristics of the installation, such as the weight and width of the door to be controlled, and its location within the building. The closing power of the closer therefore must be related not only to the size and weight of the door, but also to the operating environment at a particular location. Since the physical characteristics of doors vary greatly, even in single building installations, it has heretofore been a substantial problem to provide door closers which are individually designed to suit each particular door installation.

To alleviate the foregoing problem, it is the object of this invention to provide a spring adjustment mechanism, for use in a door closer or. the like, which has a broad range of power characteristics which can be adjusted in the field to adapt the mechanism to the requirements of the particular installation. The invention permits, for example, a single adjustable closer design to be made and sold for a wide range of door conditions, and thereby reduces the costs of the closer manufacturer and user. Furthermore, the present invention provides a door closer design which permits a substantial increase in potential biasing power of the unit without a substantial increasein size, weight, or manufacturing costs. The present invention, due to its adjustability in the field, also allows great versatility in the choice of door closer operating characteristics and power curves (e.g., closing force measured against the degree of door opening).

Briefly described, the mechanism of the present invention comprises a cylinder housing embodying a slideable piston. An adjustable biasing mechanism is provided in the housing for urging the translation of the piston in the cylinder. The biasing mechanism comprises a plurality of biasing means, such as compression springs, which are extended in the housing in engagement with the piston and arranged to apply individual biasing forces to the piston. The individual biasing forces join to produce a resultant piston-driving force. Load adjustment means are provided in the mechanism to vary the individual biasing force of each biasing means, and thereby proportionately vary the resultant piston-driving force.

Further objects and advantages of the present invention will become more apparent from the following brief description of an embodiment thereof, taken in conjunction withthe accompanying drawings, in which:

FIG. 1 is a cross-sectional view of a door closer unit embodying the adjustable mechanism of the present invention, illustrating the unit in its initial adjustment position;

FIG. 2 is a partial sectional view of the closer unit illustratedin FIG. 1, showing'the unit in a second adjustment position;

FIG. 3 is a partial sectional view of the door closer unit of FIG. 1, illustrating the unit in a third adjustment position;

FIG; 4 is a partial sectional view of the door closer unit'of FIG. 1, showing the unit in a fourth adjustment position; and

FIG. 5 is a cross-sectional end view of the unit, taken along the line 5-5 in FIG. I.

The door closer unit embodying the features and advantages of the present invention is generally indicated in the drawings by the reference numeral 10. This closer 10 includes a cylinder housing 12 of standard construction. Mounting means 14 are provided on the housing 12 to permit the housing to be mounted on a door or door frame orthe like, at any desired location. Removable end caps 16 and 18 seal both ends of the housing.

The closer 10 also includes a piston 20 slideably positioned within the cylinder housing 12. In the illustrated embodiment, the piston 20 includes a rack 22 which engages with the gear teeth on a rotatable pinion 24. As well known by those skilled in the art, this arrangement permits the rotational motion of pinion 24 to be converted into translating movement of the piston 20 within the cylinder 12, and vice versa. Accordingly, a door control arm or other suitable linking mechanism (not shown) can be connected to the pinion 24 so that the movement of the door being controlled is interrelated to the sliding movement of the piston 20 within the cylinder 12. Specifically, in the illustrated embodiment the opening of a door would cause counterclockwise rotation of the pinion 24. The pinion 24 in turn acts through the rack 22 to slide the piston 20 to the right within the cylinder 12, as illustrated in FIG. 1. In the same regard, a force applied to the piston 20 urging the piston to the left in FIG. 1 would operate through the rack 22 and pinion 24 to close the door.

In accordance with this invention, the closer unit 10 further includes an adjustable biasing mechanism for urging the translation of the piston 20 in the cylinder 12, to urge an opened door closed under controlled conditions. In this regard, the illustrated unit 10 is provided with a plurality of biasing means in the form of compression springs 30, 32 and 34, as clearly shown in FIG. 1. The springs 30, 32 and 34 are extended in the cylinder 12 toward the cap 18, with one end of each spring in engagement with the slideable piston 20. Each ofthese springs 30, 32, 34 is selected to have a spring rate and other operating characteristics which suit the particular design requirements for the installation in which the closer is to be used. As shown in FIG. 1, each spring is arranged to exert a biasing force, to the left in FIG. 1, which resists the rightward movement of the piston 20 within the cylinder 12. The springs join together to apply a resultant spring force to the piston 20 which urges the piston to the left after the springs have been compressed. The springs thereby operate to urge the door being controlled into a closed position, by returning the piston 20 to the left in FIG. 1.

In accordance with this invention, the closer unit 10 also includes an adjustment mechanism for varying the operating characteristics of each of the springs 30, 32 and 34, to thereby proportionately vary the resultant door closing forces applied to the piston 20. Accordingly, the unit includes a plurality of annular concentric adjustment members 40, 42 and 44 which are telescoped together adjacent the end cap 18. These members 40, 42 and 44 are co-axially arranged generally along the axis of the cylinder 12, and are in axial alignment with the concentric springs 30, 32 and 34.

As illustrated clearly in the drawings, the springs and members are arranged so that the springs 30, 32 and 34 are engaged with the members 40, 42'and 44, respec-' tively. The smaller members 40 and 42 include peripheral flanges 40a and 42a respectively, which are de-.

signed to engage aligned abutment shoulders 42b and 44b provided on the next largest members 42 and 44, respectively. Hence, the flange 40a of the member 40 will abut against the annular shoulder 42b of the member 42. Similarly, the flange 42a will engage with the annular shoulder 44b. By this arrangement, axial translation of the smallest member 40 into a position such as illustrated in FIGS. 2 through 4 of the drawings, will cause the members 40, 42 and 44 to telescope withrespect to each other as a result of the engagement of the flanges and the shoulders described above. Of course, the position of the flanges and the axial length of each of the members 40, 42 and 44 can be adjusted to provide the desired operating characteristics for the adjustment mechanism in accordance with this invention.

The closer 10 also includes adjustment means in the form of a screw shaft 50 for translating the members 40, 42 and 44 in the manner described above. As illustrated in the drawings, the shaft 50 extends through the end cap 18 of the unit 10, and is threadably engaged with the smallest adjustment member 40. A suitable bearing and seal combination 52 in the end cap 18 permits the shaft 50 to be rotated freely during the operation of the adjustment mechanism. Further, a nut 54 is provided on the outer end of the shaft 50 so that the shaft can be readily rotated from the outside of the unit 10. A shoulder 56 on the shaft 50 defines the limit of axial translatory advance of the member 40 along the shaft 50.

The operation of the door closer 10 is evident from the above description. Briefly, the initial position for the adjustable door loser 10 is the position illustrated in FIG. 1. In that initial position, the adjustment screw 50 is set so that the adjustment members 40, 42 and 44 are telescoped in a closed condition. The aligned springs 30, 32 and 34 are thereby extended between the aligned members 40, 42 and 44 and the piston 20. In the usual circumstance, the springs 30, 32 and 34 are provided with a pre-load force which urges the piston 20 to the left in FIG. 1 in this initial position. Under these conditions, the total biasing force applied to the piston 20 is the resultant of the individual spring forces of the three biasing springs 30, 32 and 34. Hence, the opening of an associated door, and the resultant counterclockwise rotation of the pinion 24, will cause the piston 20 to move rightward in FIG. 1, in opposition to this resultant biasing force.

When the door is released, the stored energy in the compressed springs 30, 32 and 34 will act on the piston 20 to urge the piston in a leftward direction in FIG. 1. Accordingly, the springs 30, 32 and 34 operate to ro tate the pinion 24 in a clockwise direction, and thereby urge the associated door to return to its closed condition. The power curve for such a door closing operation depends upon the spring rates and the other physical characteristics. of each of the springs 30, 32 and 34. As will be evident to those skilled in the art, the size,

power, and other operating characteristics of these I springs can be selected and modified to suit the particular design parameters.

In accordance with this invention, the operating characteristics of the door closer 10 can be adjusted in the field'to suit the requirements of a particular installation. Accordingly, if the closer I0 is to be employed in an installation requiring additional spring power,the closer 10 may be installed and then adjusted manually by rotation of the nut 54, This operation of the nut 54 rotates the screw shaft 50, and threadably advances the adjustment member 40 longitudinally within the cylinder 12. As illustrated in FIG. 2, this threaded advance of member 40 causes an increase in the compression preload force on the aligned compression spring 30. The spring force of the spring 30 is thereby changed, and the total resultant biasing force applied to the piston 20 is proportionately varied.

If additional spring power is required for the installation, the adjustment of the nut 54 can be continued until the flange 40a engages with the shoulder 42b. The further advancement of the screw shaft 50 causes the translation of the next largest adjustment member42.

As illustrated in FIG. 3, the longitudinal translation of the adjustment member 42 increases the pre-load com-: pression force on the aligned spring 32. At the same time, the continued threaded advancement of the member 40 along the shaft 50 further pre-loads the spring 30 a selected-amount, depending upon the axial length of the member 40. By this arrangement, the individual biasing force of bothsprings 30 and 32 is increased, and the resultant biasing force or spring power applied to the piston 20 again is proportionately increased.

Finally, if a substantial spring power is needed for a particular installation, the unit 10 can be adjusted to provide an even further increasein biasing force. As

illustrated in FIG. 4, furtherrotation of the nut 54'will advance the flange 42a into engagement with the shoulder 44b, and cause longitudinal translation of the largest adjustment member 44. At the same time, the position of the two smaller adjustment members 40 and 42 are comparably advanced along the screw shaft 50. By this arrangement, the pre-load biasing force of the larg-- est spring 34, aligned with the adjustment member 44 is increased a selected amount. At the same time, the pre-load on the power springs 30 and 32 is proportionately increased. The resultant spring force applied to the piston 20 is thereby increased substantially by a selected amount when the closer is adjusted to the maximum power position illustrated in FIG. 4.

It will be noted from the above description that the closer 10 in accordance with this invention has great versatility. Because of its adjustable features, it can be used in a variety of installations which would otherwise require individual units with different operating power characteristics. The troublesome matching of a special unit with each field installation is eliminated by permitting easy andquick adjustmentof the power rate of the unit in the field. Furthermore, because of the inclusion of the plurality of springs. 30, 32 and 34, the individual characteristics of each of the springs can be selected to provide the closer 10 with adesired power curve.

While .the embodiment described herein is at present considered to be preferred, it is understood that various modifications and improvements may be made therein, and it is intended to cover in the appended claims all such modifications and improvements as fall within the true spirit and scope of the invention.

What is desired to be claimed and secured by Letters Patent of the United States is:-

1. An adjustable spring loadingmechanism comprising:

a cylinder housing;

a piston slidable in said cylinder; and

an adjustable biasing mechanism for urging the translation of said piston in said cylinder comprising a plurality of substantially concentric compression springs extended within said cylinder in connection with said piston and arranged to apply individual biasing forces to said piston which cooperate to produce a resultant pistondriving force, a plurality of load adjustment members positioned for translation within said housing and telescoped together adjacent one end of said springs, said load adjustment members being further arranged with one member in axial alignment with each spring for engagement therewith, and adjustment means to selectively telescope said members axially within said housing to apply a pre-load force to the associated spring which varies the individual biasing force of said spring and thereby varies the resultant piston-driving force.

2. An adjustable spring loading mechanism in accordance with claim 1 wherein said adjustment means comprises a screw thread arranged to advance said adjustment members axially against said springs.

3. An adjustable door closer mechanism comprising: a cylinder housing;

a piston slideable in said cylinder;

connecting means for linking said piston to a door so that said piston moves in response to the movement of the door; and

an adjustable biasing mechanism for urging the translation of said piston comprising a plurality of concentric springs extended within said cylinder in connection with said piston and arranged to apply individual biasing forces to said piston which cooperate to produce a resultant door-closing force, a plurality of concentric load adjustment members telescoped together adjacent one end of said springs and arranged with one member in engagement with each spring, and adjustment means connected to said members and operative to telescope said members axially against the associated spring and thereby vary said individual spring biasing force and vary the resultant door-closing force.

4. An adjustable door closer mechanism in accordance with claim 3 wherein said adjustment members comprise a series of telescoped annular members arranged so that each member is engaged and is in axial alignment with one of said concentric springs, with the smaller of said telescoped members having abutment means arranged to engage with the adjacent larger member so that the movement of each member induces movement of said adjacent larger member, and further wherein said adjustment means comprises a shaft threadably engaged with the smallest telescoped member, whereby the threaded advance of said shaft moves said smallest member axially to telescope said members with respect to each other and to apply a selected preload force to each of said springs in response to the axial movement of the associated adjustment member. l l l 

1. An adjustable spring loading mechanism comprising: a cylinder housing; a piston slidable in said cylinder; and an adjustable biasing mechanism for urging the translation of said piston in said cylinder comprising a plurality of substantially concentric compression springs extended within said cylinder in connection with said piston and arranged to apply individual biasing forces to said piston which cooperate to produce a resultant piston-driving force, a plurality of load adjustment members positioned for translation within said housing and telescoped together adjacent one end of said springs, said load adjustment members being further arranged with one member in axial alignment with eacH spring for engagement therewith, and adjustment means to selectively telescope said members axially within said housing to apply a pre-load force to the associated spring which varies the individual biasing force of said spring and thereby varies the resultant piston-driving force.
 2. An adjustable spring loading mechanism in accordance with claim 1 wherein said adjustment means comprises a screw thread arranged to advance said adjustment members axially against said springs.
 3. An adjustable door closer mechanism comprising: a cylinder housing; a piston slideable in said cylinder; connecting means for linking said piston to a door so that said piston moves in response to the movement of the door; and an adjustable biasing mechanism for urging the translation of said piston comprising a plurality of concentric springs extended within said cylinder in connection with said piston and arranged to apply individual biasing forces to said piston which cooperate to produce a resultant door-closing force, a plurality of concentric load adjustment members telescoped together adjacent one end of said springs and arranged with one member in engagement with each spring, and adjustment means connected to said members and operative to telescope said members axially against the associated spring and thereby vary said individual spring biasing force and vary the resultant door-closing force.
 4. An adjustable door closer mechanism in accordance with claim 3 wherein said adjustment members comprise a series of telescoped annular members arranged so that each member is engaged and is in axial alignment with one of said concentric springs, with the smaller of said telescoped members having abutment means arranged to engage with the adjacent larger member so that the movement of each member induces movement of said adjacent larger member, and further wherein said adjustment means comprises a shaft threadably engaged with the smallest telescoped member, whereby the threaded advance of said shaft moves said smallest member axially to telescope said members with respect to each other and to apply a selected pre-load force to each of said springs in response to the axial movement of the associated adjustment member. 